In a reflector antenna[?], the relative reduction in the effective aperture of the antenna caused by the masking effect of other antenna parts, such as a feed horn or a secondary reflector, which parts obstruct the radiation path.
... The racial makeup of the town is 88.27% White, 3.90% African American, 0.20% Native American, 2.13% Asian, 0.05% Pacific Islander, 3.49% from other races, and ...